dFRC (Dynamic Functional Reserve Capacity) is a real-time model of anaerobic energy availability during a ride, available to view in Analyze 360. Think of it as a battery gauge: it tracks how your anaerobic capacity drains when you push above threshold and how it recharges when your effort drops back below it. To learn more on how to interpret dFRC and use it in your post workout data analysis, check out this blog post.
What is dFRC
Dynamic Functional Reserve Capacity (dFRC) builds on your Functional Reserve Capacity (FRC), which defines the total anaerobic energy available above your threshold power (mFTP). While FRC is the size of your battery, dFRC shows you second-by-second how full or depleted that battery is throughout a workout or race.
The zero line is the key reference point: when dFRC reaches zero, your anaerobic reserve is fully depleted. Efforts above threshold drain the battery; recovery below threshold recharges it.
How to find dFRC in Analyze 360
By default, dFRC appears as a multi-channel chart that overlays power and dFRC(%) together, giving you a side-by-side view of output and anaerobic cost in a single chart.
dFRC is only available in Analyze 360. To add it to your analysis view:
- Open a workout with power data in Analyze 360.
- Click Customize to view the channel selector.
- Select one or both dFRC channels:
- dFRC (kJ) — the traditional model, displaying anaerobic reserve in kilojoules. The zero line is the key reference: when dFRC reaches zero, the athlete's anaerobic reserve is fully depleted.
- dFRC (%) — displays anaerobic reserve as a percentage of the athlete's full FRC. 100% means the battery is fully charged; 0% means it is fully depleted.
dFRC not populating?
dFRC requires FRC to be calculated before it can display. If dFRC is not appearing in a workout, follow these steps:
- Open the workout in Analyze 360.
- Navigate to the Power tab.
- Close the workout.
- Reopen the workout in Analyze 360.
dFRC will now populate.